Question: Simplify the expression. $ (7z^{3}+6z^{2}) - ( -7z^{3}-4z) + (6z^{3}-3z ) $
Explanation: Distribute any negative signs. $(7z^{3}+6z^{2}) + (7z^{3}+4z) + (6z^{3}-3z)$ Since we are adding polynomials, we can simply remove the parentheses. $7z^{3}+6z^{2} + 7z^{3}+4z + 6z^{3}-3z$ Identify like terms. $ {7 z^3} + \color{#DF0030}{6 z^2} + {7 z^3} + {4 z} + {6 z^3} - {3 z} $ Combine like terms. $ { ( 7 + 7 + 6 ) z^3} + \color{#DF0030}{ 6 z^2} + { z} $ Add the coefficients. $20z^{3}+6z^{2}+z$